The objectives of the proposed research are: (a) to study in detail the role of cyclic nucleotides and prostaglandins in the mechanism of bone cellular activation by electric currents; (b) to consolidate the recently developed stress generated potential (SGP) model with the biological finding from animal experiments; and (c) to develop clinical tools for applying electricity as an accelerating mechanism in orthodontic tooth movement. Engineering techniques will be employed to design and fabricate improved appliances in order to achieve greater miniaturization of the palatal power pack (PPP), to optimize the electrode configuration, to provide tracking electrodes and radio transmitted data on the electrical functioning of the PPP. In cat jaw tissue samples cyclic AMP levels will be measured by a protein binding technique; cGMP, PGE2 and PGF2 will be measured by radio-immunoassays. The localization and distribution of cyclic nucleotides in jaw sections will be studied immunohistochemically. Orthodontic tooth movement will be effected in young adult cats by tipping maxillary canines by coil springs. Electric currents will be applied by the PPP device to tissues surrounding moving canines. Following treatment, tissues surrounding cat maxillary canines will be examined utilizing the above quantitative and qualitative biochemical techniques.